import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scanner=new Scanner(System.in);
        System.out.println("输入一个整数:");
        int n=scanner.nextInt();
        int sum=1;
        for(int i=1;i<=n;i++){
            sum*=i;
        }
        System.out.println(n+"!的阶乘是:"+sum);
    }
}